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- PDB-8fli: Cryo-EM structure of a group II intron immediately before branching -
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Open data
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Basic information
Entry | Database: PDB / ID: 8fli | |||||||||
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Title | Cryo-EM structure of a group II intron immediately before branching | |||||||||
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![]() | SPLICING/RNA / group II intron / splicing / branching / maturase / SPLICING-RNA complex | |||||||||
Function / homology | ![]() RNA-directed DNA polymerase activity / endonuclease activity / nucleic acid binding / zinc ion binding Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.8 Å | |||||||||
![]() | Haack, D.B. / Rudolfs, B.G. / Zhang, C. / Lyumkis, D. / Toor, N. | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Structural basis of branching during RNA splicing. Authors: Daniel B Haack / Boris Rudolfs / Cheng Zhang / Dmitry Lyumkis / Navtej Toor / ![]() Abstract: Branching is a critical step in RNA splicing that is essential for 5' splice site selection. Recent spliceosome structures have led to competing models for the recognition of the invariant adenosine ...Branching is a critical step in RNA splicing that is essential for 5' splice site selection. Recent spliceosome structures have led to competing models for the recognition of the invariant adenosine at the branch point. However, there are no structures of any splicing complex with the adenosine nucleophile docked in the active site and positioned to attack the 5' splice site. Thus we lack a mechanistic understanding of adenosine selection and splice site recognition during RNA splicing. Here we present a cryo-electron microscopy structure of a group II intron that reveals that active site dynamics are coupled to the formation of a base triple within the branch-site helix that positions the 2'-OH of the adenosine for nucleophilic attack on the 5' scissile phosphate. This structure, complemented with biochemistry and comparative analyses to splicing complexes, supports a base triple model of adenosine recognition for branching within group II introns and the evolutionarily related spliceosome. | |||||||||
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 497.6 KB | Display | ![]() |
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PDB format | ![]() | 371.4 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
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-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 29279MC M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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1 |
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Components
#1: RNA chain | Mass: 289257.938 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Production host: ![]() ![]() | ||
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#2: Protein | Mass: 65065.121 Da / Num. of mol.: 1 / Mutation: G275D Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: tll0114 / Production host: ![]() ![]() | ||
#3: Chemical | Has ligand of interest | Y | |
-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: Group IIB intron in complex with its maturase protein / Type: COMPLEX / Entity ID: #1-#2 / Source: RECOMBINANT |
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Molecular weight | Experimental value: NO |
Source (natural) | Organism: ![]() ![]() |
Source (recombinant) | Organism: ![]() ![]() |
Buffer solution | pH: 7.5 |
Specimen | Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Talos Arctica / Image courtesy: FEI Company |
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Microscopy | Model: FEI TALOS ARCTICA |
Electron gun | Electron source: ![]() |
Electron lens | Mode: OTHER / Nominal defocus max: 2500 nm / Nominal defocus min: 1000 nm |
Image recording | Electron dose: 31.6 e/Å2 / Film or detector model: GATAN K2 SUMMIT (4k x 4k) |
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Processing
Software |
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | |||||||||
3D reconstruction | Resolution: 3.8 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 38881 / Symmetry type: POINT | |||||||||
Refinement | Cross valid method: NONE |